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<div class="section" id="mapping-protocol">
<span id="mapping"></span><h1>Mapping Protocol<a class="headerlink" href="#mapping-protocol" title="Permalink to this headline">¶</a></h1>
<p>See also <a class="reference internal" href="object.html#c.PyObject_GetItem" title="PyObject_GetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetItem()</span></code></a>, <a class="reference internal" href="object.html#c.PyObject_SetItem" title="PyObject_SetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_SetItem()</span></code></a> and
<a class="reference internal" href="object.html#c.PyObject_DelItem" title="PyObject_DelItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_DelItem()</span></code></a>.</p>
<dl class="function">
<dt id="c.PyMapping_Check">
int <code class="sig-name descname">PyMapping_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_Check" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">1</span></code> if the object provides mapping protocol or supports slicing,
and <code class="docutils literal notranslate"><span class="pre">0</span></code> otherwise. Note that it returns <code class="docutils literal notranslate"><span class="pre">1</span></code> for Python classes with
a <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a> method since in general case it is impossible to
determine what type of keys it supports. This function always succeeds.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_Size">
Py_ssize_t <code class="sig-name descname">PyMapping_Size</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_Size" title="Permalink to this definition">¶</a></dt>
<dt id="c.PyMapping_Length">
Py_ssize_t <code class="sig-name descname">PyMapping_Length</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_Length" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-0">Returns the number of keys in object <em>o</em> on success, and <code class="docutils literal notranslate"><span class="pre">-1</span></code> on failure.
This is equivalent to the Python expression <code class="docutils literal notranslate"><span class="pre">len(o)</span></code>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_GetItemString">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyMapping_GetItemString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em>, const char<em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_GetItemString" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return element of <em>o</em> corresponding to the string <em>key</em> or <code class="docutils literal notranslate"><span class="pre">NULL</span></code> on failure.
This is the equivalent of the Python expression <code class="docutils literal notranslate"><span class="pre">o[key]</span></code>.
See also <a class="reference internal" href="object.html#c.PyObject_GetItem" title="PyObject_GetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetItem()</span></code></a>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_SetItemString">
int <code class="sig-name descname">PyMapping_SetItemString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em>, const char<em> *key</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *v</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_SetItemString" title="Permalink to this definition">¶</a></dt>
<dd><p>Map the string <em>key</em> to the value <em>v</em> in object <em>o</em>. Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> on
failure. This is the equivalent of the Python statement <code class="docutils literal notranslate"><span class="pre">o[key]</span> <span class="pre">=</span> <span class="pre">v</span></code>.
See also <a class="reference internal" href="object.html#c.PyObject_SetItem" title="PyObject_SetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_SetItem()</span></code></a>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_DelItem">
int <code class="sig-name descname">PyMapping_DelItem</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_DelItem" title="Permalink to this definition">¶</a></dt>
<dd><p>Remove the mapping for the object <em>key</em> from the object <em>o</em>. Return <code class="docutils literal notranslate"><span class="pre">-1</span></code>
on failure. This is equivalent to the Python statement <code class="docutils literal notranslate"><span class="pre">del</span> <span class="pre">o[key]</span></code>.
This is an alias of <a class="reference internal" href="object.html#c.PyObject_DelItem" title="PyObject_DelItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_DelItem()</span></code></a>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_DelItemString">
int <code class="sig-name descname">PyMapping_DelItemString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em>, const char<em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_DelItemString" title="Permalink to this definition">¶</a></dt>
<dd><p>Remove the mapping for the string <em>key</em> from the object <em>o</em>. Return <code class="docutils literal notranslate"><span class="pre">-1</span></code>
on failure. This is equivalent to the Python statement <code class="docutils literal notranslate"><span class="pre">del</span> <span class="pre">o[key]</span></code>.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_HasKey">
int <code class="sig-name descname">PyMapping_HasKey</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_HasKey" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">1</span></code> if the mapping object has the key <em>key</em> and <code class="docutils literal notranslate"><span class="pre">0</span></code> otherwise.
This is equivalent to the Python expression <code class="docutils literal notranslate"><span class="pre">key</span> <span class="pre">in</span> <span class="pre">o</span></code>.
This function always succeeds.</p>
<p>Note that exceptions which occur while calling the <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a>
method will get suppressed.
To get error reporting use <a class="reference internal" href="object.html#c.PyObject_GetItem" title="PyObject_GetItem"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetItem()</span></code></a> instead.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_HasKeyString">
int <code class="sig-name descname">PyMapping_HasKeyString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em>, const char<em> *key</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_HasKeyString" title="Permalink to this definition">¶</a></dt>
<dd><p>Return <code class="docutils literal notranslate"><span class="pre">1</span></code> if the mapping object has the key <em>key</em> and <code class="docutils literal notranslate"><span class="pre">0</span></code> otherwise.
This is equivalent to the Python expression <code class="docutils literal notranslate"><span class="pre">key</span> <span class="pre">in</span> <span class="pre">o</span></code>.
This function always succeeds.</p>
<p>Note that exceptions which occur while calling the <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a>
method and creating a temporary string object will get suppressed.
To get error reporting use <a class="reference internal" href="#c.PyMapping_GetItemString" title="PyMapping_GetItemString"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyMapping_GetItemString()</span></code></a> instead.</p>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_Keys">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyMapping_Keys</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_Keys" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>On success, return a list of the keys in object <em>o</em>. On failure, return
<code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.7: </span>Previously, the function returned a list or a tuple.</p>
</div>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_Values">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyMapping_Values</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_Values" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>On success, return a list of the values in object <em>o</em>. On failure, return
<code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.7: </span>Previously, the function returned a list or a tuple.</p>
</div>
</dd></dl>
<dl class="function">
<dt id="c.PyMapping_Items">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyMapping_Items</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyMapping_Items" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>On success, return a list of the items in object <em>o</em>, where each item is a
tuple containing a key-value pair. On failure, return <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.7: </span>Previously, the function returned a list or a tuple.</p>
</div>
</dd></dl>
</div>
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